Storm water sewer systems typically include separator systems for reducing the amount of sediment and/or oils or other hydrocarbons present in the storm water. Because most storm water sewer systems release the storm water into a natural watercourse, such as a river, the sediments and oils can have a negative environmental impact upon the area. Sediments will tend to build up a delta and other barriers that impact the flow dynamics of the watercourse, thereby impacting upon aquatic life. Therefore, separator systems are placed throughout the storm water sewer system.
Among known separator systems are hydrodynamic separators. Some of the drawbacks of hydrodynamic separators include their low capacity, high cost, and required maintenance.
An alternative separator system is a multi-chambered separator system. Known multi-chambered separator systems have difficulty dealing with high flow rate storm water. These systems encounter re-suspension problems during high flow occurrences wherein previously captured sediment is remixed or pooled floating hydrocarbons are remixed. Some systems attempt to address this problem by completely bypassing entrainment during a high flow event and allowing full untreated flow out of the system.
Another drawback with known systems is their large footprint. The systems are located underground and require significant excavation to construct, which present difficulties in areas with limited space and with utilities or other structures in the immediate area. A related problem is that existing systems are difficult to accommodate in poor soil conditions, such as excessively soft wet soil.